In a conventional image scanning device that is capable of scanning an A4 size paper and has a platen cover hinged at a long side of the A4 size paper, the platen cover is required to be opened at a 180-degree angle to scan one page and then another page of a A4 size book by parallel shifting the book on a platen. When the platen cover cannot be opened at a 180-degree angle, it is impossible to scan one page and then another page of the A4 size book by parallel shifting the book on the platen. Due to the installation environment of the image scanning device, if the platen cover cannot be opened at a 180-degree angle, the book interferes with the platen cover during the scanning operation (parallel shifting the book on the platen).
In this situation, after an image on one page of a pair of adjacent open pages of a book is scanned, the book is horizontally inverted (the positions of the bottom and top ends of the book are reversed) on a platen to scan an image on the adjacent page of the pair of open pages of the book. There is a technology to align a direction of a scanned image to a primary direction of a scanned image through rotating the scanned image by 90 degrees, for example, see Japanese laid-open patent application publication No. H5-110813.
However, there is a problem in that it is difficult to use the technology described above. While several pages of a book are scanned continuously, if a scanned image, which is scanned after the scanning pages are inverted, is printed as it is, the direction of an image in a middle page is opposite to that of other images of other pages.